1. Field of the Invention
The present invention relates to an information processing apparatus and a method for processing information, and more specifically, to processing executed for printing an image including a tint block image, which restrains people from using duplicates and the like, in a system configured by having the information processing apparatus, such as a personal computer, and the printing apparatus, such as a printer.
2. Description of the Related Art
Conventionally, in order to prohibit copying a ledger sheet, a resident card, and the like, or restrain people from doing so, papers on which special printing is given, papers called anti-counterfeit paper have been used. The anti-counterfeit paper is a paper in which characters or the like such as “COPY” is embedded to be hard to recognized by a human eye when the paper is in a state of an original and to show up on the copied paper when the original is copied using a copying machine or the like. Thereby, people can visually distinguish a print sheet as the original from the duplicate made by copying the original, easily. The use of this anti-counterfeit paper as an original causes those who copy the original to hesitate to use duplicated papers. Moreover, the anti-counterfeit paper gives a mental restraint effect of inhibiting an act of copying itself. The reason why characters in the original of the anti-counterfeit paper needs to be hard for people to recognize is to enable people to distinguish between the original and the duplicate definitely. If characters such as “COPY” is recognizable to such an extent that people can clearly recognize it even in the original, there may occur the possibility that people recognize it as the duplicate and such paper does not make a sense as the anti-counterfeit paper. Wicker (U.S. Pat. No. 5,788,285) and Mowry et al. (U.S. Pat. No. 6,000,728) disclose arts for manufacturing such an anti-counterfeiting paper.
On the other hand, as various contents are being digitized, the contents of ledger sheets, a resident card, or the like are being transformed into digital data similarly However, digitization for handling of these ledger sheets and resident cards, such as use of these documents, is still in a transition phase. Consequently, the contents of digital data formed using a computer is likely to be outputted on papers with a printer or the like for subsequent use.
Under such circumstances, significant improvement in printer performance has been achieved in recent years, and this is one of cause for a technology, which makes it possible to print out a paper on demand that has the same effect as the conventional anti-counterfeit paper using a computer and a printer, to attract an attention. Japanese Patent Application Laid-open No. 2001-197297 discloses a technology whereby, when contents data formed using a computer is printed out with a printer, an image called tint block (a copy-forgery-inhibited pattern) is also outputted with superposed on the background of the contents data. The tint block image is an image that is recognized only as a simple pattern or a mere background color in the original (a printed matter outputted by a printer) to the human eye, but, when it is copied, will show up as predetermined characters or the like in the duplicate. Thereby, the same restraint effect as the anti-counterfeit paper can be given to those who copied.
In the case that the contents are printed out together with a tint block image generated by a computer, being superposed thereon, a normal printing paper or the like can be used. Therefore, this technology has an advantage in terms of cost in comparison with the technology using the anti-counterfeit paper. Moreover, the tint block image can be generated when the contents are outputted by printing. Thereby, characters or the like that will be basically made visible at the time of copying can be set freely. Further more, there is also an advantage that dynamic or any information, such as a user name and printout time and date, can be made to show up as the characters, in addition to static information such as “COPY”.
The tint block image, as discussed above, is one that, when being duplicated, visualizes a predetermined character or the like that could not be recognized before duplication, therefore restrains people from using the duplicate, and realizes an effect of enabling people to visually identify what the people sees to be the duplicate, in other words, not to be the original easily. In order to realize this effect, the tint block image is basically composed of two areas; an area which remains (shows up) in the duplicate when being copied, and an area which disappears in the duplicate or becomes too light-colored to recognize compared to the image remaining area. These two areas, as being printed, are of almost the same density, and therefore no one can recognize that characters etc., such as “COPY” that will become visible by duplication are hidden (embedded) therein at first sight, in a macroscopic sense However, in a microscopic sense, for example, in a level of printed dots, these two areas have different characteristics, respectively, as will be shown below. Hereafter, an image that will show up by duplication is called a “latent image” and an image that will disappear or become light-colored is called a “background” for convenience. The tint block image is basically composed of the latent image and the background image. Moreover, there is a case where the tint block image also includes a below-mentioned camouflage image. Incidentally, there may be a case where the latent image is called a foreground as a term related to a user interface.
The latent image portion or the foreground portion of the tint block image, which is an area that remains including the printed dots after duplication, consists of blocks of the concentrated printed dots. On the other hand, the background portion, which is an area whose dots disappear or whose density is made lighter after duplication, consists of the dispersed printed dots.
Note that tint block printing is not limited to the above-mentioned composition, and the tint block image may be composed in such a way that characters, such as a “COPY”, a logo, or a pattern will be rendered (will become visible) as an recognizable image to the human eye in the duplicate. That is, even if the characters “COPY” are rendered as outlined characters in the duplicate, it will achieve its object as tint block printing.
FIG. 27 is a view showing these two areas. As shown in this figure, the tint block image is composed of both the background section in which dots are arranged dispersedly and the latent image section in which concentrated dot masses are arranged. These two areas can be generated by mutually different half tone dot processing and dither processing. In the case where the tint block image is generated using the half tone dot processing, half tone dot processing with a small number of lines is suited for the latent image and that with a large number of lines is suited for the background section. In the case where the tint block image is generated using dither processing, dither processing using a dot concentration type dither matrix is suitable for the latent image section, and dither processing using a dot dispersion type dither matrix is suitable for the background section.
Generally, the copying machine has critical points in reproducing capability that depends on input resolution of reading fine dots of a manuscript and output resolution of reproducing fine dots. In the case where the dot in the background section of the tint block image is formed smaller than the critical point of dots that the copying machine can reproduce and the dot masses in the latent image section thereof are formed larger than the critical point, an image composed of larger dot masses of the tint block image is reproduced and an image composed of smaller dots is not reproduced, in the duplicate by copying. As a result, the latent image will be made visible. Moreover, even in the case where dispersed small dots are not completely disappeared by copying, i.e., in the case where the density of the background section is low compared to that of concentrated dot masses, relatively the latent image can be recognized more markedly. Such image that shows up is called a visualized image.
FIGS. 28A and 28B are views showing visualization of the latent image. FIG. 28A is a view corresponding to a state where the tint block image is printed. FIG. 28B is view corresponding to a duplicate obtained when an original image shown in FIG. 28A is copied by a copying machine. From FIG. 28A and FIG. 28B, it may be understood that the latent image by the concentrated dot masses will show up and the background by the dispersed dots will disappear.
Further, it is also known well that a technique called the “camouflage” for making it difficult to recognize a latent image embedded in the original is applied to the tint block image. The camouflage is a technique of arranging a pattern whose density is differentiated from those of the latent image section and the background section to be superposed on the tint block image. The tint block image to which the camouflage is applied has an effect that the camouflage image whose density is different from those of the latent image section and the background section becomes noticeable and the latent image section becomes further less noticeable. Moreover, the camouflage image has an effect of giving a decorative impression to a printed matter. FIG. 29A shows a tint block image to which no camouflage image is given. FIG. 29B shows a tint block image to which a camouflage image is given. In order to make it easy to recognize a visualized latent image in the duplicate after duplication, it is desirable that dots constituting the camouflage image are made not to be reproduced in the duplicate. This can be realized by, for example, drawing the camouflage image as an outlined image, as shown in FIG. 29B.
As is described above, the tint block image is one that is to be printed on the same sheet as an image (hereinafter also referred to as an original image) which is subject for applying brakes to use duplication of that image. Conventionally, during tint block printing, the tint block image is printed across the entire face of a physical sheet (page) on which the original image is to be printed. More specifically, conventionally, whether tint block printing should be applied is individually determined for each physical page. For example, as is described in Japanese Patent Application Laid-open No. 2001-197297, a page for the printing of the tint block image is specified, and the original image and the tint block image are printed on the specified page, without especially specifying an area for printing the tint block image. For this printing, a watermark printing method is employed whereby an original image, in the background of a tint block image, is overwritten, or a superimposition method is employed whereby an OR operation or an AND operation is performed for a tint block image and an original image, and as the obtained results, the tint block image is printed. This can make interference between these images avoided to minimize any reduction in the quality of the original image as much as possible, especially when the area for printing the original image and the area for printing the tint block image are overlapped.
For a problem of controlling the degradation of the quality of the original image, a technique is also available that can specify an area for the printing of a tint block image. According to this technique, for the form printing of debit notes or bonds, a data file (definition data) for tint block printing is prepared separately from data related to the form. Then when the form is to be output, data related to the tint block printing, which are prepared in advance, are obtained to generate a tint block image. Thereafter, the thus produced tint block image and the image of the form are synthesized, and the result is printed out (see Japanese Patent Application Laid-open No. 2001-324898).
However, even when a printing method such as the watermark printing or the superimposition printing described in Japanese Patent Application Laid-open No. 2001-197297 is employed, preventing the quality of the original image from being degraded may be insufficient. For example, for a predetermined image, such as the portrait of a person, that is constructed of an outline portion and a gradation (changing) portion, which are formed of dots, and a blank portion, in which no dots are formed, when the dots used for the tint block image are formed in a part of the blank portion or the gradation portion, the impression got from the image may differ from that of the original, or the image itself may not easily be identified. Further, even if the original image is a character, depending on the printing method employed, the character obtained may be partially got chipped by the tint block image. Furthermore, when the above described camouflage is employed to a tint block image, the camouflage pattern would give an especially strong impression, and degradation of the quality would be more noticeable.
At the same time, some methods are considered in which an area for the tint block image being applied or an area for the tint block image being not applied can be specified to avoid overlapping itself of the printing areas for the original image and the tint block image.
As one of these methods, it may be considered that a pre-printed sheet, on which a tint block image has previously been printed in accordance with a given area of an image form to correspond to the specific original image form, is employed. That is, the pre-printed sheet is not a sheet on which the tint block image is printed over an entire area of the sheet but is a sheet on which the tint block image is printed on only the given area. However, this method differs from the previously described technique whereby a tint block image is output with an original image by using a printer, and is of the same type as the above described technique used for anti-counterfeit sheet. Therefore, basically, the same problems are encountered with this method. More specifically, since such pre-printed sheets are generally expensive and are used only in the printing of specific forms, there is a greater increase in costs. And furthermore, if the printing forms were changed, the pre-printed sheets for tint block images would also have to be changed, so that on taking time and cost expenditures into consideration, the method that uses pre-printed sheets is not economical.
Other methods may be considered, like one described in Japanese Patent Application Laid-open No. 2001-324898. In the method, a special application, which has a function for previously generating a tint block image of a given size which is separate from an original image such as forms, is employed to generate and store a tint block image, and then the stored tint block image is read out and is combined with the original image when printing is performed. However, since the style of the generated tint block image is specialized for the application, it is not possible to apply a tint block image with specifying an area to which the tint block image is to be applied, in connection with an original image such as a document that is generated by another application. That is, so long as the layout of an image to be printed is not known previously, an area on which a tint block image is to be printed, or an area on which the tint block image is not to be printed, can not be specified.
In addition, according to this method, a definition file for specifying the location and the size of a tint block image must be prepared in advance. Thus, it may be often difficult for a user to display image data for which printing is desired (a preview display), and while confirming the image data, to specify a size and a location for an area wherein a tint block image is applied, or for an area wherein the tint block image is not applied. That is, since the area used for a tint block image must be defined in advance, it is difficult to say that, for a user, the degree of freedom and the usability of specifying an area used for a tint block image are high for data having various styles and layouts. Of course, the definition file must be rewritten for changing the layout of data and thus changing the layouts is a very painful operation for the user. That is, this technique can not easily specify a tint block image, which is to be combined, at an arbitrary area of an original image, whatever the type of the original image is.